<?php
// +----------------------------------------------------------------------
// | quanli team
// +----------------------------------------------------------------------
// | Copyright (c) 2013-2020 http://www.fistforward.com/ All rights reserved.
// +----------------------------------------------------------------------
// | Author: allen.qiang
// +----------------------------------------------------------------------

/**
 * 检查一个坐标是否在一个范围里（多边形、圆形等）
 * @package  htdocs
 * @version 1.0
 */
class quanliPointLocation {

    private $pointOnVertex = true; //检查坐标是否在顶点

    /**
     * 多边形
     */
    public function polygon($point, $polygon, $pointOnVertex = true) {

        $this->pointOnVertex = $pointOnVertex;

        //切割坐标，放到一个数组里

        //坐标
        $point = $this->pointStringToCoordinates( $point );

        //坐标集合
        $vertices = array();
        foreach ($polygon as $vertex) {
            $vertices[] = $this->pointStringToCoordinates($vertex);
        }

        //检查坐标是否在顶点
        if ($this->pointOnVertex == true && $this->pointOnVertex($point, $vertices) == true) {
            return true;
        }

        // Check if the point is inside the polygon or on the boundary
        $intersections = 0;
        $vertices_count = count($vertices);

        for ($i=1; $i < $vertices_count; $i++) {
            $vertex1 = $vertices[$i-1];
            $vertex2 = $vertices[$i];
            if ($vertex1['y'] == $vertex2['y'] and $vertex1['y'] == $point['y'] and $point['x'] > min($vertex1['x'], $vertex2['x']) and $point['x'] < max($vertex1['x'], $vertex2['x'])) { // Check if point is on an horizontal polygon boundary
                return true;
            }
            if ($point['y'] > min($vertex1['y'], $vertex2['y']) and $point['y'] <= max($vertex1['y'], $vertex2['y']) and $point['x'] <= max($vertex1['x'], $vertex2['x']) and $vertex1['y'] != $vertex2['y']) {
                $xinters = ($point['y'] - $vertex1['y']) * ($vertex2['x'] - $vertex1['x']) / ($vertex2['y'] - $vertex1['y']) + $vertex1['x'];
                if ($xinters == $point['x']) { // Check if point is on the polygon boundary (other than horizontal)
                    return true;
                }
                if ($vertex1['x'] == $vertex2['x'] || $point['x'] <= $xinters) {
                    $intersections++;
                }
            }
        }
        // If the number of edges we passed through is odd, then it's in the polygon. 
        if ($intersections % 2 != 0) {
            return true;
        } else {
            return false;
        }

    }

    /**
     * 检查坐标是否在顶点
     * @param array $point 坐标数组
     * @param array $vertices 坐标集合数组
     * @return bool
     */
    private function pointOnVertex($point, $vertices) {
        foreach($vertices as $vertex) {
            if ($point == $vertex) {
                return true;
            }
        }
        return false;
    }

    /**
     * 切割坐标，放到一个数组里
     * @param string $pointString 坐标字符串，如‘121.345994,31.151189’
     * @return array
     */
    private function pointStringToCoordinates( $pointString ) {
        $coordinates = explode(',', $pointString);
        return array('x' => $coordinates[0], 'y' => $coordinates[1]);
    }

}